From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752612AbcGVQEr (ORCPT ); Fri, 22 Jul 2016 12:04:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45366 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751244AbcGVQEq (ORCPT ); Fri, 22 Jul 2016 12:04:46 -0400 From: Bandan Das To: Paolo Bonzini Cc: Dave Jones , Linux Kernel , Radim =?utf-8?B?S3LEjW3DocWZ?= , kvm@vger.kernel.org Subject: Re: RFC: silencing kvm unimplemented msr spew. References: <20160715192729.GA4712@fb.com> <110045299.8101686.1468855610053.JavaMail.zimbra@redhat.com> <20160719195856.GA31453@fb.com> <20160721202440.GA10908@fb.com> <844431780.9635789.1469177321917.JavaMail.zimbra@redhat.com> Date: Fri, 22 Jul 2016 12:04:40 -0400 In-Reply-To: <844431780.9635789.1469177321917.JavaMail.zimbra@redhat.com> (Paolo Bonzini's message of "Fri, 22 Jul 2016 04:48:41 -0400 (EDT)") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 22 Jul 2016 16:04:45 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo Bonzini writes: ... >> Yeah, that's close. Though I would have done the same for the other side of >> the if's too. >> (Still evaluating which mode is actually more useful for us). > > For Linux guests, there should be no reason to use ignore_msrs. Linux > is pretty resilient to "missing" MSRs (especially because they are already > ignored if the kernel is compiled with CONFIG_PARAVIRT=y!). The option is > really more for Windows, because it doesn't have anything like CONFIG_PARAVIRT > and because drivers are sometimes less vetted (and sometimes do RDMSR > themselves for whatever reason). In general we try to look at beta versions > of Windows and add any required MSRs well before the final release date, > but if you're using old kernels you might be stuck with ignore_msrs. > > IOW, if there was a really common reason to use ignore_msrs it would be > the default. ;) > >> Paolo, would you prefer this, or the other approach you already ack'd ? > > I think I prefer the other, because vcpu_debug is not ratelimited. > If the guest can trigger a printk it should always be ratelimited. Agree with rate limiting, but making this the default for everything doesn't sound right IMO, especially for ignore_msrs=1. vcpu_unimpl is already rate limited. Or is this change specifically to suppress messages on ignore_msrs=1 ? > Paolo > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html